Oil-sealed shaft bearing



Se t. 7, 1954 R ANNEN 2,688,521

OIL-SEALED SHAFT BEARING Filed Aug. 6, 1951 I I5' M33 Patented Sept. 7, 1954 OIL-SEALED SHAFT BEARING Robert Annen, Bienne, Switzerland, assignor to Roulements a Billes Miniatures S. A., Bienne, Switzerland, a joint-stock company Application August 6, 1951, Serial No. 240,504

Claims priority, application Switzerland August 11, 1950 9 Claims.

This invention relates to shaft bearings and more especially antifriction bearings.

It is an object of this invention to provide bearings of this kind, in which a cap or cover closing as a separate member the part of the bearing traversed by the shaft is spaced or separated from this part of the bearing by a capillary gap capable of maintaining between the bearing and the shaft a thin oil film serving to close the gap between the shaft and the bearing.

Bearings of the kind aforesaid have already been disclosed in prior patents. The bearing according to the present invention distinguishes over the prior art bearings of a similar kind by the fact that the capillary gap constitutes the narrowest section of an annular space having a cross-section which gradually increases in size towards the outside, so as to provide for the oil in the gap the possibility of moving away from the capillary gap whenever the pressure in the interior of the bearing rises relative to the outer pressure, the oil being however free to return into the gap in proportion as the inner and outer pressures approach each other again.

Such rises of pressure in the interior relative to the pressure on the outside of the bearing arise quite particularly in the case where the bearing forms part of a motor or other apparatus operating in an airplane, for in that case the outside pressure is the atmospheric pressure which drops at higher altitudes, while the inner pressure cannot drop owing to the fact that bearings of this kind are as a rule enclosed in a closed space from which no air can escape. Therefore the inner pressure practically remains at least equal to the atmospheric pressure near the ground where the bearing has been mounted in place, rising however more or less during operation in viewof rises of temperature, for instance due to friction, which causes the air in the inner bearing space to expand.

It is also important to note that the bearing according to the preesnt invention is distinguished from bearings resembling it at first sight by the fact that the oil film forming a sort of packing is able not only to move away from the capillary gap during such rises of the pressure in the interior relative to the pressure on the outside, but will also be returned towards and into the gap in the proportion as the values of the inner and the outer pressures again approach each other, an occurrence which does not take place in the bearings hitherto known.

In the drawings aflixed to this specification and forming part thereof, some embodiments of a bearing according to the present invention are illustrated diagrammatically by way of example.

In the drawings Figs. 1, 2 and 3 are cross-sections of a first, second and third embodiment, respectively, all of them having the form of ball bearings.

Figs. 4 and 5 are similar views of a fourth and fifth embodiment, respectively, the former being a roller bearing, while the latter supports a cylindrical shaft.

Fig. 6 is an end view of an inner cap or cover of the kind operating also in Fig. 2.

Referring to the drawings and first to Fig. 1,

the ball bearing here shown comprises an outer casing I, balls 2, a ball cage 3, while 4 is part of a shaft journal in which the inner ball race 5 is formed.

A cover 6 in the form of a disc perforated in the center is retained in position by an annular disc 1 whose border section 8 is beaded and formed with radial slots, resting on the peripheral part of the disc 6 which is supported by a washer I0 resting on a shoulder 9 of the casing I.

A similar combination of parts is provided in the same arrangement at both ends of the bearing, the caps or covers 6 form radial flanges of at least approximately cylindrical sleeves II which arespaced from the part of the bearing (in this case the shaft journal) which extends through them, by a capillary gap I2 containing the oil film. Both these gaps I2 constitute the narrowest section of an annular space I3, whose section rises progressively towards the outside so that the film is free to move away from the capillary gap I2 when the pressure within the bearing rises relative to the outer pressure, being however returned towards the gap in proportion as the inner and outer pressures again approach each other. When the shaft journal 4 is at rest, the return of the oil film into the gap I2 occurs under the action of the capillary force. When the shaft rotates, the return of the oil film into the capillary gap is induced not only bythe capillary forces, but apart therefrom also by the combined action of the centrifugal force and the surface tension acting along the part of the shaft delimiting the annular space from the inside. In fact this part of the shaft or the bearing is constituted by a conical surface l4 whose diameter increases from the outside towards the inside of the bearing.

Means are provided for maintaining a certain quantity of oil spread along the tubular sleeves I I forming part of the cover 6. In the case here shown these means are constituted by longitudiments have shown that in the practical use of these bearings the semi-angle at the peaigof the.

surfaces 14 should preferably fall within the range of 8 and 20.

The second embodiment shown in Figs; 2 and 6 is distinguished from the first one merely by the fact that here the slots t5; ail-1c rep a ed by: an inner cover l6 also comprising a sleeve and extending alongside of the cover 6 with very narrow spacing due to the bosses I611. which determine the width of a capillary gap I! extendinginto close proximity of the capillary gap l2. The inner cover. 16, thnsiorms to ether with. the outer cover 6a m ans, allowing. to. maintain y capillary action a certain quantity of oil, spread all. along the cylin r cal sleeve 18: forming. p r of. h

cov r t9, analogous. to: the cover 6 i the fir t embodiment.

Y The other parts of. the bearine-asiar as h y are identical with similar parts of. the. first embodiment. r mark d with the same reference numerals.

Thethird embo im n h wn-in. Fig. 3 is distinguished from thefirst one merely by the fact that here the ball bearing comprises, apartfrom theouter casing 20, an inner sleeve 2], balls. 22, a. ballcage 21-3 and sealing piec s 6,. l and ID. of t e kind lready described. in. respect of F g- The annular space l3, the narrowest section. of which. is constituted by the capillary gap [2, is delimited on the; inside. by a conical surface 24 of the inner bearing. sleeve 2| which is also the part of the bearing that. extends through the two covers 6..

The embodim nt of. Fig. 4 is dist nguished from, the one shown. i E'ig. 3. only by the fact that it. is a rol er b aring comprising an outer casing 25, an inn r sl eve 26-. roll rs 2- and th same sealing parts 6,] and It as, were described with reference to Figs- 1 an 3.. Th embodiment. also shows the capillary slots 15 and th capillary gaps. i2 whichv constitute the narrowest sections of the. annular spac It d limit d n. th in ide by h conic l urfaces 28, correbonding. to the c nical surface 24. of. the thir embodiment, and. to the co ical uriaces M of the first. and. secon embodim nt The mbodim nt of. Fla 5. is a y ndri al. hearing for a. cylindrical: sh ft. ournal. 2.9. i compris san outer asin 30 formed; with a borin at which is filled by a aring; brass preferably f an ifric n m tal. This em odiment furth r c mprises the same a-lingnar s 6 l; and ill as pp ar in the first, thi d and fourth embo m n The longi udina gro ves form d in the circumference of. the brass enable the oil. t c p towards the bo tom af r having acted as lubricant on the contactnl suriaces of the brass 32 and th journal 2-81. This l tter here constitu-tes the part of. he bearing w i h s; rmed with conical surfaces as resembling the sur a e M in the first embodiment and delimiting on their inner parts the annular spaces. 1.3,

It is clear that one. m ght change th embo m nts according to Figs. 3. 4 and 5. n the. same manner as the embodiment oi F g.- l was changed by that shown in. Fig. 2.. In. oth r words. on

n ne si e.

4 might replace the slotted cover 6 by a cover l9 combined with an inner cover l6. Apart therefrom it should also be noted that the capillary gaps constituted either by the slots I5 or by the spaces enclosed between the two covers l6 and lerneed not be of uniformwidth throughout. They might for instance narrow down slightly, starting from the capillary gap l2, in order to provide by capillary action some suction effect on. the, oil, On the other hand they might also narrow down slightly near the capillary gap in order to direct the oil by capillary action towards this gap.

The faces M, 24, 28 and 34 need not be conical, but should always form a face inclined from the outside towards the inside at an angle preferably ranging between 8 and 20.

All the bearings shown in the drawings as well as the modified forms of the bearings mentioned above can operate in any desired position in na e. In. th posi on repres n ed. in. F sl'. 4 d 5, t e l wer. over const t s. an oil reset voir. from. whic the oil is led by ap llary a t toward the. n igh orin gap. I2 which it onc t e b r ng a b en. turned. aro n o instance on being wrapped, From this. place t e o l'will retu n to. the. uria es to be lub cated when, the. bearing, is in operation without it be.- ing ne essary. to..1.nal;e any pr parat n Th s has been tained conv ncing y by tests made nde eatly vary g o d on Obviously th nvention. i n t. m ted. t b arings. entirely tr versed by a. s af but w ll e quall use ul n onne tion th be ri s losed n is ase the c ve 6 o 9 is replaced on that side by a centra ly o ed. cove which. may be r d. r astic. he latter ase this cover will. con t tute n elast c membrane wh ch will give w y o a ce tai extent o; ilfer nces. betwe n e oute and. t e nn r p s- SW1 I Wish t to e unde to d t at I. d ot d sir to. e im ted. to. th deta l shown nd des ribed for obvious. modifications w l; ccur to. a pe on skilled. n. h artl laimz.

An o l-sealed sh it= arina more especiall tor a r crait ev es. c mpr sing i c mbination an ou er c si a ro ary shal member x ndins therethroueh. antii lction m ansin erte be tween the ou e ca ing and s d sha m mber, a substantiall y ndr cal s eeve r und ng. sai shaft member and spaced tb ir m. to. form a api ary ab erew th to h rme ca l eal; th b ring. a d sleeve enc os ng with said member n outward y o ening an l r ng n betwee .8 and 20.".

2.. An. oil-sealed shai bear ng omp ising. n comb n tion. an oute as ng pen a both e ds, ro ary sha t. member e tending h ou h said casing, antifriction means inserted between the uter casing and. said shaft member, a epar substanti lly yl nd ical lee su ro ding said sha t. m m and spaced. there rom on each side o s id nt i iotion m an o f rm ap l ar gaps th r with to. he metically eal he be ring said. sleeves enclosing w th said shal membe outwardly openin opposit ang es rang n between Bf and 29- 3. An oil-sealed shaft=bearins c m r sin n combina on. outer a r ta y shaf -incinber xtending into sa d. casina. a tii ctionmoan inserted etween the casing and a d s af member. a. subs an ia ly c lindr al sl eve su ou ing said shaft. memb r and spaced therefr m to form a capillary gap therewith to hermetically seal the bearing, said sleeve enclosing with said shaft member an outwardly opening angle ranging between 8 and 20"., and another sleeve fixedly nested in the first-mentioned sleeve and spaced therefrom to form a capillary space leading to the capillary gap.

4. Oil-sealed shaft-bearing, comprising in combination, a bearing box, a shaft and a bearing element on said shaft extending into said box, antifriction elements in said box inserted between the box walls and said bearing element, a substantially cylindrical sleeve surrounding said bearing element in spaced relation, means seated in said box for centering said sleeve in said box, a body of oil in said box and axially extending slits in the wall of said sleeve up to the free end of said sleeve, said sleeve enclosing with said bearing element an angle, opening towards said shaft, ranging between 8 and 20.

5. The oil-sealed shaft bearing of claim 1, in which that part of the shaft which extends through the cylindrical sleeve surrounding it, is formed with an outwardly diminishing diameter so as to create in said sleeve an oil chamber widening toward the outside.

6. The oil-sealed shaft bearing of claim 1, in

which the shaft member surrounded by the cylindrical sleeve is provided with an outwardly diminishing diameter forming an angle with a cylindrical sleeve ranging between 8 and 20.

'7. The oil-sealed shaft bearing of claim 1, in which the bearing element extending through the cylinder sleeve is a sleeve closely fitting the shaft and formed with conical end sections.

8. The oil-sealed shaft bearing of claim 1, in which the inner race for the antifriction bearings is formed in a conical frustum of outwardly diminishing diameter.

9. An oil-sealed shaft bearing of claim 3 in which the shaft member surrounded by the cylindrical sleeve is provided with an outwardly diminishing diameter forming an angle with the cylindrical sleeve ranging between 8 and 20.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,895,288 Larsh Jan. 24, 1933 1,930,586 Delaval-Crow Oct. 17, 1933 1,958,907 Brouwer May 15, 1934 2,000,276 Delaval-C'row May '7, 1935 2,05%,582 Delaval-Crow Sept. 15, 1936 

